####018006405#### FXUS63 KDVN 160437 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 1137 PM CDT Thu May 15 2025 ...Updated for 06z Aviation... .KEY MESSAGES... - A conditional threat for severe storms (level 2 of 5) remains this afternoon and early evening across northwest and north central Illinois. - Humid and breezy conditions today with near record highs, with most locations hitting the upper 80s to lower 90s. - Strong southwest winds are forecast on Friday, potentially peaking 40 - 45+ mph. - Active weather returns early next week, with widespread beneficial rain likely. && .SHORT TERM /THROUGH TONIGHT/... Issued at 110 PM CDT Thu May 15 2025 The forecast remains on track today with hot and humid conditions ahead of a cold front which is currently approaching the far western portion of the outlook area. A potent, negatively tilted trough will swing through the Upper Midwest today, and an unseasonably strong surface low (~980mb) nearly vertically stacked with the upper-low will shift through eastern South Dakota into far southeast North Dakota into this evening. This system will push a cold front through eastern Iowa and northwest Illinois through the mid to late afternoon, marking a SSE to WSW wind shift and significant drop in low-level moisture with dewpoints falling from the upper 60s/near 70 F down into the 50s. Ahead of the front, diurnal BL mixing will aid in pushing temperatures to near record highs as very warm air at 850mb (near 20 C) is adiabatically mixed down to the surface. This will yield highs in the low 90s for counties along and east of the Mississippi River. SPC has maintained a Slight Risk (level 2 of 5) for severe storms in the counties east and northeast of the Quad Cities, with a small area of an Enhanced Risk (level 3 of 5) in eastern Stephenson County. A Marginal Risk (level 1 of 5) extends back to the west toward the Quad Cities. While the forecast environment is favorable for severe storms this afternoon due to high instability with MLCAPE of 2500+ J/kg and sufficient deep layer shear for storm organization, CAMs have continued to show relatively low areal coverage, although with a wide variance in solutions. The HRRR continues to be one of the least aggressive with CI in our outlook area, holding off development until either near or east of our eastern border. Other CAMs such as the NSSL/ARW/NAMnest develop scattered storms along and just east of the Mississippi River between 3 to 5 PM. And this is likely the worst case scenario for today -- scattered strong to severe storms impacting the eastern tier or two of counties during the late afternoon/early evening, before the activity quickly shifts to the east. The other possible scenario is for the area of low-level convergence along and slightly downstream of the surface front to progress far enough to the east through the afternoon that CI is primarily focused east of the outlook area during the late afternoon to early evening. As mentioned, the environmental setup is there to support severe storms, so any convection that does develop could quickly become severe with large hail and damaging winds the primary threats, and an isolated tornado secondary. Dry conditions are expected overnight with lows in the 60s and 50s. && .LONG TERM /FRIDAY THROUGH THURSDAY/... Issued at 110 PM CDT Thu May 15 2025 Friday: Warm and windy conditions are expected with a much drier post-frontal air mass in place. The strong area of low pressure will remain positioned across west-central MN to southeast ND which will keep a tight pressure gradient over eastern Iowa and northwest Illinois. Strong, gusty SW to WSW winds are forecast locally with peak values around 45 mph possible and a Wind Advisory may eventually be needed. Low-level moisture will be much lower than on Thursday, but with dewpoints in the mid 40s to lower 50s there may be enough instability during the afternoon to lead to high-based isolated showers and storms, which could locally enhance the winds to 50+ mph. Forecast soundings display MUCAPE of 500+ J/kg and DCAPE near 1200 J/kg. On a separate note, since significant green-up of vegetation and area grasses has already occurred this spring the fire weather threat should be muted. Nonetheless, given the strong gusty winds, dry conditions, and low afternoon humidity between 20-30%, burning is discouraged on Friday. Saturday - Sunday: Seasonable weather is forecast for the upcoming weekend with highs in the 60s across the north and 70s elsewhere. It will be breezy on Saturday with NW winds gusting around 30 mph. No precipitation is expected through Sunday evening. Next Week: Models are in good agreement on an active weather pattern setting up for the early to middle portion of next week with periods of widespread rainfall likely. NBM highs are in the 60s and 70s. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1130 PM CDT Thu May 15 2025 VFR conditions are anticipated for much of the period. A brief period of LLWS is still forecast late tonight for CID and DBQ. Otherwise, another windy day is on tap for the terminals on Friday with gusts 30-40 kt at times from the southwest. There is a low chance (20 percent) for a shower or storm this afternoon, but confidence is too low for mention. Late Friday afternoon and evening, lower clouds with MVFR ceilings are expected to spread across at least the northern terminals (DBQ and CID) around low pressure over Minnesota. Confidence on these ceilings developing at MLI or BRL is too low for mention. Winds will veer to more westerly Friday evening and remain gusty at times. && .CLIMATE... Issued at 220 PM CDT Wed May 14 2025 Record High Temperatures: May 15: KBRL: 93 / 1944 KCID: 94 / 1941 KDBQ: 90 / 1944 KMLI: 91 / 1941 Record Warm Low Temperatures: May 15: KDBQ: 67 / 2001 KMLI: 69 / 2001 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...Uttech LONG TERM...Uttech AVIATION...McClure CLIMATE...Gross ####018005652#### FXUS66 KOTX 160439 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 939 PM PDT Thu May 15 2025 .KEY MESSAGES... - Light Rain for the Idaho Panhandle and Eastern Washington overnight into Friday morning - Increasing rain showers on Saturday into Sunday with a 20-30% chance of thunderstorms Saturday afternoon && .SYNOPSIS... A cool and showery weather pattern will continue through at least early next week. In addition, breezy winds are expected at times. && .DISCUSSION... Tonight through Friday Night: A weakening and stretching frontal boundary moving into western Washington this afternoon will cross the Cascades into Central WA this evening, and then into Eastern WA/N Idaho overnight into Friday morning. Despite the weakening nature, models are in good agreement that as the front encounters the rising terrain of Eastern WA/N Idaho light rain will develop. Also boosting confidence in the high moisture content with this wave as precipitable water values increase to 125-140 percent of normal. For Central WA weak downslope flow off the Cascades combined with dry air in the lower levels to initially overcome is expected to result in little to no rain for places like Omak, Wenatchee, and Moses Lake. Friday afternoon as this wave exits showers will become focused over the orographically favored terrain of NE Washington and the ID Panhandle. For Friday Night the next system approaches with a chance of showers mainly in the Cascades and NE Washington. JW Friday night through Sunday morning: A low pressure system off the coast of the Pacific Northwest will begin spinning up Friday evening into Saturday. By Sunday, the system will be moving southeast and stretching, centered over Idaho and Utah. This system will bring a rainy weekend to most of the forecast area. Ensembles and clusters are still struggling with the track of the low, with half the WPC clusters favoring the low swinging further south and the other half showing it staying a bit north of Utah. There is also the chance for a deformation band to move through the Lewiston/Pullman/southern Panhandle area, which could lead to higher rain amounts. Currently, in far eastern Washington (Spokane/Pullman/Northeast Blue Mountains) and the Idaho Panhandle have a 30 percent chance or higher of seeing at least a quarter inch of rain between Saturday and Sunday afternoon. Other parts of the forecast area, including the Cascades and areas east of Omak, have a 20 percent chance or higher of seeing a wetting (0.1 inches) amount of rain, with those percentages increasing as you move eastward. On Saturday afternoon, as the trough axis is sitting right above us, there will be enough lift for a chance of thunderstorms. While SBCAPE is relatively low (100 to 200 J/kg), there could be a few isolated thunderstorms throughout the day across the forecast area. As such, the SPC has us in general thunderstorms Saturday afternoon and evening. The heaviest rain will occur late Saturday night through Sunday afternoon, with the highest rainfall totals anticipated in the southern Panhandle and the Northern Mountains. Due to the aforementioned ensemble model disagreement, we will keep a close eye on this system in the next few days, as any major changes in the low pressure track have the potential to change rainfall totals. After the low pressure system moves out of the area, weather will remain slightly unsettled with light bouts of precipitation as small waves move through. This precipitation will be mainly confined to the mountains due to orographic lift. As mostly dry conditions prevail, temperatures will rise back into the mid to high 60s for much of the area. Right now, due to much of the area outside of the mountains being dry after the weekend storm, the CPC's 6-10 and 8-14 Day Outlooks have the forecast area either at near normal or leaning below normal precipitation through the end of May. /AS && .AVIATION... 06Z TAFS: VFR conditions will continue through 12z tonight. A system comes in overnight, with a chance for -ra over TAF sites. Around 12-14z, light rain will increase over the eastern TAF sites, with widespread MVFR conditions expected to develop. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: MVFR conditions will develop overnight. ----------------------- Confidence descriptors: Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance For additional probabilistic information for NWS Spokane airports, please refer to the Aviation Dashboard on our webpage: https:/www.weather.gov/otx/avndashboard && .Preliminary Point Temps/PoPs... Spokane 44 57 44 64 45 57 / 40 70 20 60 60 60 Coeur d'Alene 43 54 41 65 45 55 / 30 70 20 60 60 70 Pullman 42 55 41 61 42 55 / 40 70 10 60 70 60 Lewiston 48 62 46 69 49 61 / 50 70 10 60 70 60 Colville 43 56 39 63 39 60 / 20 60 40 70 60 60 Sandpoint 43 54 42 64 44 54 / 20 70 40 60 60 80 Kellogg 42 52 43 62 47 50 / 30 70 20 50 70 80 Moses Lake 46 69 49 68 45 67 / 20 20 10 60 40 10 Wenatchee 47 68 49 66 48 63 / 20 10 10 60 30 10 Omak 47 65 46 65 44 65 / 20 40 20 70 60 20 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...None. ID...None. && $$